EP1004273A2 - Systeme tomographique - Google Patents

Systeme tomographique Download PDF

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Publication number
EP1004273A2
EP1004273A2 EP99308787A EP99308787A EP1004273A2 EP 1004273 A2 EP1004273 A2 EP 1004273A2 EP 99308787 A EP99308787 A EP 99308787A EP 99308787 A EP99308787 A EP 99308787A EP 1004273 A2 EP1004273 A2 EP 1004273A2
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EP
European Patent Office
Prior art keywords
slice
views
view
radiation
interest
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP99308787A
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German (de)
English (en)
Other versions
EP1004273A3 (fr
EP1004273B1 (fr
Inventor
Zhongmin Lin
Leonard F. Plut
Timothy J. Crish
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke Philips NV
Original Assignee
Picker International Inc
Marconi Medical Systems Inc
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Publication date
Application filed by Picker International Inc, Marconi Medical Systems Inc filed Critical Picker International Inc
Publication of EP1004273A2 publication Critical patent/EP1004273A2/fr
Publication of EP1004273A3 publication Critical patent/EP1004273A3/fr
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Publication of EP1004273B1 publication Critical patent/EP1004273B1/fr
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/03—Computed tomography [CT]
    • A61B6/032—Transmission computed tomography [CT]

Definitions

  • the present invention relates to a tomographic system, especially for diagnostic imaging. It finds particular application in conjunction with the real-time display of medical diagnostic images and will be described with particular reference thereto. However, it is to be appreciated that the invention may find application in conjunction with non-medical imaging, volumetric imaging, and the like.
  • x-rays have been projected through a patient onto a flat film box on the other side of the patient.
  • X-ray film mounted in the film box was exposed with a projection of the radiation opacity of the tissue or other internal structure of an examined subject. Because all of the internal structure was projected into a common plane, such images were difficult to read.
  • Conventional x-ray tomographic systems have a similar construction, but include structure for moving the x-ray tube and the film box counter-cyclically in planes parallel to the x-ray film. More specifically, a centre ray of the x-ray beam was projected through the region of interest to the detector. The x-ray source and the detector were then moved such that the central ray pivots about a fixed point in the plane of interest. With this process, not only does the central ray pivot about the plane or slice of interest, the other rays from the x-ray source to the film box do as well. In this manner, the x-ray attenuation contribution to the final image from volumetric elements within the selected plane remains constant during the imaging procedure.
  • each of the rays pass through different surrounding tissue or structures as the source and detector move. In this manner, the contributions to the final image from structures outside of the plane of interest become blurred and averaged. With a sufficiently long exposure and motion through a relatively wide range, the out-of-slice structures can be reduced to background noise while the in-slice structures are displayed crisp and clear. Such systems required a significant time lag before the diagnostic image could be viewed. First, there was a delay while the x-ray source and the film box and the film box were moved back and forth to expose the film. This was followed by a further delay as the film was developed.
  • Real-time images were available from fluoroscopy systems.
  • a fluoroscopy system the x-rays are projected through the patient onto an image intensifier, i.e., a fluorescent screen and electronics to make the resultant image brighter.
  • a video camera was mounted to view the image generated by the image intensifier.
  • the video camera was connected by a closed-circuit TV system with a monitor for viewing the fluoroscopic images.
  • image intensifiers were subject to non-uniform brightness across the field-of-view and significant image distortions. Fluoroscopic images typically had much less resolution than projection x-ray.
  • CT scanners have been utilized to generate images of internal structures quickly.
  • CT scanners typically view the patient in slices which are orthogonal to those of the tomographic x-ray systems. That is, with the patient positioned prone on his back in the scanner, the tomographic x-ray systems generated an image of a horizontal slice. With the same orientation of the patient, CT scanners generate a vertical slice.
  • CT scanners can be utilized to generate a large multiplicity of slices to define a volume from which a horizontal slice can be extracted.
  • taking a large number of slices again introduces a time delay.
  • CT scanners are expensive and capable of performing only a limited number of diagnostic tasks.
  • a method of diagnostic imaging is provided.
  • a beam of radiation is projected through a region of interest of an object.
  • the radiation beam and the region of interest are moved relative to each other such that the beam passes through a stack of focal planes in the region of interest with a plurality of angular orientations about an axis perpendicular to the focal planes.
  • the beam of radiation which has passed through the stack of focal planes is converted into a plurality of electronic views.
  • Each view is a summation of projections through the focal planes, with the projections of each focal plane being shifted relative to the projections of the other focal planes in accordance with the angular orientation of the beam relative to the focal planes.
  • the relative movement is monitored and a view correction factor is determined in accordance with (i) the relative angular orientation of the radiation beam and the focal planes and (ii) a selected one of the focal planes to be imaged.
  • Each view is corrected with the determined correction factor.
  • the corrected views are combined to generate an electronic slice image representation depicting radiation opacity of structures in a slice defined by the selected focal plane.
  • an apparatus for diagnostic imaging projects a beam of penetrating radiation through a region of interest of an object on a support which supports the region of interest of the object to be examined.
  • a movable gantry causes relative motion between the radiation source and the region of interest.
  • a radiation detector detects the beam of penetrating radiation and converts the detected radiation into a plurality of electronic views during the relative movement between the radiation source and the region of interest.
  • An image processing circuit includes a means for monitoring the relative movement and determining a view correction factor in accordance with (i) a relative position of the radiation source relative to the focal planes and (ii) a selected one of the focal planes to be imaged.
  • the image processing circuit includes a means for correcting each view in accordance with a corresponding view correction factor. Finally, the image processing circuit includes a means for combining corrected views to generate an electronic slice image representation depicting radiation opacity of structures in the slice defined by the selected focal plane.
  • a radiation source 10 such as an x-ray tube, projects a beam of x-rays or other penetrating radiation through a region of interest 12 of a subject 14 , such as a patient or an object in a manufacturing environment, supported on a support 16. Radiation which has passed through the region of interest impinges upon a flat panel radiation detector 18 .
  • the radiation detector is a grid of amorphous silicon elements on the order of a millimetre square, with the overall detector being on the order of 45 cm x 45 cm. Each element of the amorphous silicon detector integrates the intensity of received radiation over a sampling period and generates an electronic data value indicative of the intensity of received radiation.
  • all of the elements are read out concurrently or in close temporal proximity to generate a view representative of x-ray intensity variation, which, in turn, is indicative of a projection of radiation opacity of the region of interest taken in the direction of the x-ray beam.
  • the radiation source 10 is mounted on a rotational gantry 20 which rotates the radiation source 10 in an annular, preferably circular, trajectory 22 of adjustable radius.
  • the gantry 20 is illustrated as a concave dish of constant radius relative to a centre point of the detector 18 .
  • the x-ray source 10 can be mounted to a dish segment supported by rollers or bearings with an adjustment drive (not shown) for adjusting the position of the radiation source 10 radially.
  • another drive motor 24 rotates the x-ray source 10 around the selected trajectory.
  • a position encoder 26 measures the radius r of the trajectory 22 and the angular position ⁇ of the x-ray source 10 around the trajectory 22.
  • the region of interest 12 is divisible into a series of focal planes F 1 , F 2 , ..., F n .
  • the image of the incremental element 32 now impinges on a point ( x i , y i, z 0 ) on the radiation detector 18.
  • the image of the incremental elements 32 traverses a complementary trajectory 22' on the detector 18.
  • the projection of point 34 and other incremental elements of the region of interest that are off the focal plane F 1 will sometimes contribute to one pixel of the integrated image and sometimes to others, thus blurring and becoming de-emphasized. With sufficient variation, the out of plane contribution to the image can be reduced to background noise.
  • the trajectory 22' can be precalculated. In this manner, for any given position ( r , ⁇ ) of the x-ray source around the trajectory 22, the offset ( x 0 -x i, y 0 -y i , z o -z i ) can be determined geometrically and stored. It is further to be appreciated that the same principle holds true for elements on focal plane F 2 and the other focal planes through F n
  • the encoder 26 monitors the radius r of the trajectory and the angular position ⁇ of the radiation source 10 around it.
  • the look-up table 40 is also addressed with the location of the focal plane to be imaged as input by an operator on a slice or focal plane selection input device 42.
  • each time a view is read out of the detector 18 passes to a view memory or buffer 44 .
  • An image translation or shift circuit 46 shifts and interpolates the resultant image by the amount S to create a shifted view which is stored in a shifted view memory or buffer 48 .
  • buffers 44 and 48 are shown separately for simplicity of illustration, it is to be appreciated that they may be the same element of hardware as may other memories described hereinbelow.
  • Each shifted image is integrated in summation circuit 50 with precedingly taken images and stored in a first slice memory 52.
  • the first slice memory 52 is used to accumulate the sum of the views taken over 180° of rotation about the trajectory 22 .
  • the first slice memory 52 is interconnected with a video processor 54 which converts the slice image representation from the memory 52 into appropriate format for display on a video monitor 56 .
  • the x-ray source 10 is rotating through the next 180° and another image is being built in a second slice memory 58 .
  • the second slice 58 memory is connected with the video processor 54 and the first slice memory 52 is erased and commences building the next view of the slice.
  • the x-ray source 10 is rotated at 15 rotations per second such that there is a frame rate of 30 images of the slice generated per second to match a standard video image frame rate.
  • frame rates may be selected such as 4-8 images per second.
  • the x-ray source 10 is rotated at 2-4 rotations per second.
  • images may be built based on shorter arc segments such as 120°.
  • the image may be built in a single memory with the oldest view being subtracted back out as the newest view is added in.
  • the views can be continuously accumulated in the slice image memory with no deletions, possibly with the accumulated image and the new view being weighted that more recent views have greater prominence than older views.
  • the angular position of the x-ray source 10 is monitored by a frame rate controller 60 which changes the position of a switch 62 after each 180° or other selected distance along the trajectory 22 .
  • the switch 62 switches which of the memories 52, 58 is connected with the video processor 54 and which is receiving the additional views from the summation circuit 50.
  • a plurality of planes or slices can be reconstructed.
  • the look-up table 40 is addressed with each of the focal planes selected with the slice selection control 42 .
  • the appropriate displacements for each of the focal planes S 1 , S 2 ..., S n are outputted to a respective image shifting circuit 46 2 , ..., 46 n .
  • the shifted views are conveyed to shifted view memories or buffers 48 2 , ..., 48 n.
  • the shifted views are summed 50 2 , ..., 50 n into the accumulating image in buffer 52 2 , ..., 52 n or 58 2 , ..., 58 n .
  • the switch circuits 62 2 , ..., 62 n convey the most recently completed slice images to a volumetric image memory 64 .
  • the volumetric image memory 64 then conveys the completed slice images through a digital enhancer 66 after the video processor 54 accesses the volumetric image memory 64 to retrieve operator selected slices, an oblique slice, volume renderings, volume images, or the like.
  • the image processing systems 68 1 , 68 2 , ..., 68 n receive inputs from the view memory 44 and Look-Up-Table 40 , which are sent to the image transition/shift circuit 46, and they receive inputs the frame rate controller 60 which is sent to the switch 62.
  • the image processing systems 68 1 , 68 2 , ..., 68 n then outputs the volume image generated to the volume image memory 64.
  • the operator can select a desired slice thickness with a slice thickness selection input device 70.
  • the selected slice thickness is used as an input into a thickness/radius look-up table 72 .
  • the look-up table 72 retrieves the corresponding trajectory radius r .
  • a radius adjustment driver 74 moves the radial position of the radiation source 10 inward or outward in accordance with the selected slice thickness and adjusts the direction of a collimator 76 such that a central ray of the radiation beam is aligned with the centre of the detector 18.
  • the radiation beam crosses the point 32 on the selected focal plane at a sharp angle. Due to the sharp angle, incremental elements only a relatively short distance off the focal plane are not held focused with the point 32 as the radiation source moves. In this manner, only data which spans a relatively narrow region to either side of the focal plane remains coherent, hence the resultant image is of a relatively thin slice.
  • the central rays intersect at point 32 at very close angles. When the central ray oscillates about a very narrow range, structures that lie over a more significant distance to either side of the focal plane remain coherently focused on the detector as the radiation source 10 rotates.
  • the resultant image represents a relatively thick slice.
  • the exact thickness of the slice versus the radius is a relatively straightforward geometric calculation based on the size of the detector elements, the displacement between the detector and the focal plane, the distance between the focal plane and the radiation source, and the radius of the trajectory 22.
  • the radiation source 10 is below the subject 14 in the preferred embodiment, for mechanical simplicity it is contemplated that the radiation source 10 may be disposed above the patient 14 with the detector 18 disposed below or built into the patient support 16.
  • trajectory 22 is defined along a spherical surface segment, for mathematical simplicity in operating on the resultant data, it is to be appreciated that the trajectories of various sizes could be defined on a flat surface or other surface.
  • each view is subject to the same shift vector S. In some circumstances, it may be advantageous to shift different portions of each view differently. Such differential shifting may reduce edge distortion, may be used to generate oblique plane views, and the like.
  • slice images built in slice image memories 52 and 54 are digital images which can be enhanced using any of a variety of image enhancement techniques. Such techniques include edge enhancement, smoothing, background noise suppression, and the like.
  • a first advantage of the real-time tomographic system described is that it provides a new imaging modality for diagnostic imaging. Another advantage is that it provides a real-time display of slices taken longitudinally through a patient. Other advantages reside in the ready adjustability of the slice thickness and position.
  • the present system is amenable to imaging in other modes including tomographic, fluoroscopic, and projection x-ray modes.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Medical Informatics (AREA)
  • Optics & Photonics (AREA)
  • Biomedical Technology (AREA)
  • Biophysics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Theoretical Computer Science (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Pulmonology (AREA)
  • Pathology (AREA)
  • Radiology & Medical Imaging (AREA)
  • Physics & Mathematics (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Apparatus For Radiation Diagnosis (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
EP99308787A 1998-11-25 1999-11-04 Système et méthode de tomographie Expired - Lifetime EP1004273B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US09/200,651 US6222902B1 (en) 1998-11-25 1998-11-25 Real-time tomographic system with flat panel detectors
US200651 1998-11-25

Publications (3)

Publication Number Publication Date
EP1004273A2 true EP1004273A2 (fr) 2000-05-31
EP1004273A3 EP1004273A3 (fr) 2001-05-16
EP1004273B1 EP1004273B1 (fr) 2007-02-21

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EP99308787A Expired - Lifetime EP1004273B1 (fr) 1998-11-25 1999-11-04 Système et méthode de tomographie

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US (1) US6222902B1 (fr)
EP (1) EP1004273B1 (fr)
JP (1) JP2000157526A (fr)
DE (1) DE69935193T2 (fr)

Cited By (2)

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FR2838905A1 (fr) * 2002-03-28 2003-10-24 Ge Med Sys Global Tech Co Llc Procede et appareil pour fournir des ajustements de decalage et de gain dependants du signal pour un detecteur de rayons x a solide
CN111336373A (zh) * 2018-12-19 2020-06-26 深圳市通用测试系统有限公司 用于无线终端测量的测试转台

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JP4417459B2 (ja) * 1999-01-11 2010-02-17 株式会社東芝 Ｘ線診断装置
US6483890B1 (en) * 2000-12-01 2002-11-19 Koninklijke Philips Electronics, N.V. Digital x-ray imaging apparatus with a multiple position irradiation source and improved spatial resolution
US6748046B2 (en) * 2000-12-06 2004-06-08 Teradyne, Inc. Off-center tomosynthesis
US6914958B2 (en) * 2001-07-06 2005-07-05 Ge Medical Systems Global Technology Company, Llc Multi-plane acquisition in digital x-ray radiography
US7003072B2 (en) * 2001-12-21 2006-02-21 Koninklijke Philips Electronics, N.V. Method for localizing a target in an object
US6882700B2 (en) * 2002-04-15 2005-04-19 General Electric Company Tomosynthesis X-ray mammogram system and method with automatic drive system
US6940943B2 (en) * 2002-10-07 2005-09-06 General Electric Company Continuous scan tomosynthesis system and method
JP4603823B2 (ja) * 2003-10-14 2010-12-22 キヤノン株式会社 放射線撮像装置、放射線撮像方法及びプログラム
CN101039622B (zh) * 2004-10-11 2011-09-07 皇家飞利浦电子股份有限公司 产生高质量x射线投影的成像系统
EP1886257A1 (fr) 2005-05-11 2008-02-13 Optosecurity Inc. Procede et systeme d'inspection de bagages, de conteneurs de fret ou de personnes
US20070041613A1 (en) * 2005-05-11 2007-02-22 Luc Perron Database of target objects suitable for use in screening receptacles or people and method and apparatus for generating same
US7991242B2 (en) 2005-05-11 2011-08-02 Optosecurity Inc. Apparatus, method and system for screening receptacles and persons, having image distortion correction functionality
US7899232B2 (en) 2006-05-11 2011-03-01 Optosecurity Inc. Method and apparatus for providing threat image projection (TIP) in a luggage screening system, and luggage screening system implementing same
US8494210B2 (en) 2007-03-30 2013-07-23 Optosecurity Inc. User interface for use in security screening providing image enhancement capabilities and apparatus for implementing same
US7817773B2 (en) * 2007-01-05 2010-10-19 Dexela Limited Variable speed three-dimensional imaging system
CN101963582B (zh) * 2010-09-13 2012-03-14 深圳大学 一种三维荧光纳米显微成像方法、系统及成像设备
KR102067367B1 (ko) 2011-09-07 2020-02-11 라피스캔 시스템스, 인코포레이티드 적하목록 데이터를 이미징/검출 프로세싱에 통합시킨 x-선 검사 방법
US10846860B2 (en) 2013-03-05 2020-11-24 Nview Medical Inc. Systems and methods for x-ray tomosynthesis image reconstruction
US10070828B2 (en) 2013-03-05 2018-09-11 Nview Medical Inc. Imaging systems and related apparatus and methods
JP6379785B2 (ja) * 2014-07-18 2018-08-29 コニカミノルタ株式会社 断層画像生成システム
EP3772702A3 (fr) 2016-02-22 2021-05-19 Rapiscan Systems, Inc. Procédés de traitement des images radiographiques
CN105844687B (zh) * 2016-04-07 2019-04-30 北京雅森科技发展有限公司 用于处理医学影像的装置和方法
WO2019060843A1 (fr) 2017-09-22 2019-03-28 Nview Medical Inc. Reconstruction d'image à l'aide de régularisateurs d'apprentissage machine
US10779791B2 (en) 2018-03-16 2020-09-22 General Electric Company System and method for mobile X-ray imaging
CN112057091B (zh) * 2020-08-18 2021-08-03 北京唯迈医疗设备有限公司 一种调速手闸机构及其调速方法

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Publication number Priority date Publication date Assignee Title
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CN111336373A (zh) * 2018-12-19 2020-06-26 深圳市通用测试系统有限公司 用于无线终端测量的测试转台
CN111336373B (zh) * 2018-12-19 2022-03-25 深圳市通用测试系统有限公司 用于无线终端测量的测试转台

Also Published As

Publication number Publication date
EP1004273A3 (fr) 2001-05-16
EP1004273B1 (fr) 2007-02-21
JP2000157526A (ja) 2000-06-13
US6222902B1 (en) 2001-04-24
DE69935193D1 (de) 2007-04-05
DE69935193T2 (de) 2007-10-25

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